Chapter 17 & 18: Archaea and Eukaryotic Microbes

Microbiology

Define Archaea

Named for the Archaean eon, when life first spread across Earth

What cells likely contributed to the origin of Eukarya?

Archaeal cells

What is nearly diverse as Bacteria but are difficult to culture?

Archaea

What are the groups Archaea is split into?

Euryarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, and Nanoarchaeota

What are the common traits of Archaea

Ether-linked lipids, lack of peptidoglycan in cell walls, and structurally complex RNA polymerases similar to those of Eukarya

What are the contemporary species that are metabolically diverse of Archaea

Chemoorganotrophs or chemolithotrophs; respiratory or fermentative; aerobic or anaerobic

What is the only domain that makes methane

Archaea

Examples of extremophiles

Hyperthermophiles, halophiles, acidophiles, and psychrophiles

Define Euryarchaeota

A physiologically diverse group of Archaea that is strict anaerobic methanogens; obligate aerobic extreme halophiles

Examples of hyperthermophiles

Thermococcus, Pyrococcus

Examples of Hyperthermophilic methanogens

Methanopyrus

Define Haloarchaea

Extremely halophilic, diverse Archaea that live in high salt (hypersaline) environments that require high salt concentrations

Define cytoplasmic Halobacterium enzymes

Highly acidic, require K+ for activity, and have fewer hydrophobic amino acids

Define Thermoplasmatales

Archaea that lack cell walls

Define Thermoplasma

A small genome that evolved unique cytoplasmic membrane structure to survive osmotic stress and withstand low pH and high temperature

Define Asgard Archaea

All information from metagenomics analyses

Define Lokiarchaeota

Genomes contain eukaryotic signature genes (membrane remodeling and cytoskeleton); near Loki’s Castle vent system between Greenland and Norway

Genera of Asgard Archaea

Lokiarchaeota, Thorarchaeota, Heimdallarchaeota, Odinarchaeota

Define Crenarchaeota

Most hyperthermophilic Archaea that is isolated from geothermally heated soils or water containing S and H2S

What is the temperature where liquid water is only found where geothermally heated water is in the ocean?

>100 C

Define Eukarya

Microbial eukaryotes can be defined by their morphology as protists, algae, or fungi; Ancestors had complex cell structure and true organelles

Define Protist

Any microbial eukaryote that is not a plant, animal, or fungus

Define Diplomonads

Have 2 nuclei of equal size and very reduced mitochondria

Define Giardia intestinalis

Causes giardiasis, a common waterborne intestinal disease

Define Parabasalids

Contain a parabasal body, lack mitochondria but have hydrogenosomes for anaerobic metabolism, and most genomes lack introns

Define Kinetoplastids

Live primarily in aquatic habitats, feeding on bacteria; some species are parasites of animals and cause serious diseases

Define kinetoplast

A mass of DNA present in their single large mitochondrion

What causes African sleeping sickness

Trypanosoma Brucei

What is the causative agent of Chagas disease

Trypanosoma cruzi

Define Euglenids

Nonpathogenic, contain chloroplasts used when living in light, lose chloroplast- can exist as chemoorganotrophs

Define Ciliates

Possess cilia, most widely distributed genus is Paramecium, and use cilia for motility and to obtain food

What are the 2 nuclei of ciliates?

macronuclei and micronuclei

Define Dinoflagellates

Diverse marine and freshwater phototrophic organisms, have 2 flagella with different insertion points on the cell

Define Pfiesteria Piscicida

A genus of toxic dinoflagellate responsible for massive fish kills

Define Diatoms

Over 100,000 species in freshwater and marine habitats that exhibit radial and pinnate symmetry; appeared on Earth about 200 million years ago

Define frustules

Cell walls are made of silica

Define oomycetes

Also called water molds based on their filamentous growth and the presence of coenocytic hyphae; cell walls are made of cellulose

Define Phytophthora Infestans

Causes the late blight disease in potatoes and contributed to the Irish Potato Famine

What doe Terrestrial and aquatic protists use for movement and feeding?

Pseudopodia

Major groups of terrestrial and aquatic protists

Gymnamoebas, entamoebas, plasmodial and cellular slime molds

Define Entamoebas

parasites of vertebrates and invertebrates

What do hyphae form?

Compact tufts called mycelia with a large surface area to volume ratio, well adapted to absorptive nutrition

Define conidia

Asexual spores that are produced from hyphae that extend above the surface of fungi; often pigmented and resistant to drying

What are most fungal cell walls made of?

Chitin

What helps plants obtain phosphorus and nitrogen?

Mycorrhizae

Define Mycorrhizae

symbiotic associations with plant roots

Define fruiting bodies

Macroscopic reproductive structures produced by some fungi

What are examples of fruiting bodies?

mushrooms and puffballs

Key genera of Ascomycota

Saccharomyces, Candida, Aspergillus

Define Ascomycota

A highly diverse phyla, with examples of baker’s yeast and common molds

What are the mating types in the yeast Saccharomyces cerevisiae?

Mating (sexual reproduction) and via conidia that form at the tips of specialized hyphae called conidiosphores (asexual reproduction)

Define Basidiomycota

Recognizable as mushrooms and toadstools; undergo both vegetative and sexual reproduction.